coronavirus variants

BA.4, BA.5 and More: What We Know About COVID-19 Variants

NBCUniversal Media, LLC

The omicron variant of the COVID-19 virus has been driving coronavirus infections for more than eight months, but the number of subvariants of that strain can be a dizzying list to navigate through.

To help, we have assembled a list of the most common subvariants of omicron, according to the CDC, and given information on when they originated, the threats that they pose, and even what all of those numbers mean.

Omicron Subvariants


The original omicron subvariant, first detected in South Africa in Nov. 2021, was named as a variant of concern by the World Health Organization shortly after it was discovered.

By December it had reached the United States, and it spread rapidly, with a much-higher transmissibility rate than the delta variant of COVID.

Other variants subsequently emerged, and this lineage has made up less than 1% of COVID cases in the U.S. for most of 2022.

Considered the most contagious COVID-19 subvariants to date, BA.4 and BA.5 have fueled surges in case counts across the country, including in the Midwest, where both have become predominant strains.


By the spring of 2022, the BA.2 omicron subvariant had become the dominant strain of COVID in the United States, making up more than 73% of cases in early April.  

Along with BA.2.12.1, this strain helped drive cases upward in the spring, and was 50% more transmissible than the B.1.1.529 subvariant, according to the White House’s chief medical adviser, Dr. Anthony Fauci.

Fortunately for most patients, infection with the BA.1 or B.1.1.529 subvariants generally provided good protection against BA.2.

BA.2 now makes up just 1.4% of COVID cases in the United States.


Many residents may have been confused by BA.2.12.1’s lengthy identification number, but the reason for it is simple: this subvariant is the 12th lineage to branch off from the original BA.2, and there were also branches off of that, hence the "1" at the end of its designation.

The subvariant was the dominant strain of COVID in the United States for several months.

Even with the emergence of other variants, this strain still makes up 17.3% of COVID cases as of this week, making it the second-most prevalent subvariant in the United States.

As two more contagious omicron subvariants take hold across the U.S., you may be wondering what steps to take if you test positive for COVID-19.


The fourth “version,” for lack of a better term, of the omicron variant is now one of the more prevalent strains of the virus in the United States, making up 16.3% of cases as of Tuesday.


The BA.5 subvariant is now the dominant strain of COVID in the United States, making up nearly two-thirds of cases, and this particular version of the virus is more adept at evading preexisting immunity than other strains.

Changes to the virus have allowed it to escape antibodies from vaccinations and from previous COVID infections, even cases that resulted from other omicron subvariants, according to CDC data.

As a result, researchers fear that more individuals may be sickened by this subvariant, but vaccinations and previous illness still appear to protect against severe illness or hospitalization, officials say.

The quickly changing coronavirus has spawned yet another super contagious omicron mutant that’s worrying scientists as it gains ground in India and pops up in numerous other countries, including the United States.

Other Subvariants


This latest subvariant of the virus has been detected in the United States, but was first identified in India, where it is causing a spike in cases.

Officials say that this subvariant, which came from the BA.2 version of omicron, could have similar ability to evade antibodies to that of the BA.4 and BA.5 subvariants, but more worryingly it could also evade antibodies created by infection from the original BA.2 strain, officials say.

Still, all information on BA.2.75 is very preliminary, and officials caution that there have not been enough cases in the United States to get an accurate picture of just how big a threat the subvariant could become.

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